[CRIU] [PATCH 1/2] Re-create cgroups if necessary

[Pavel Emelyanov]

On 06/23/2014 10:53 PM, Andrew Vagin wrote:
> On Mon, Jun 23, 2014 at 10:29:53PM +0400, Andrew Vagin wrote:
>> On Mon, Jun 23, 2014 at 03:54:22PM +0000, Tycho Andersen wrote:
>>> If a task had cgroups, these should be restored. (Also any properties of
>>> cgroups, but this commit doesn't do that yet.)
>>>
>>> Signed-off-by: Tycho Andersen <tycho.andersen at canonical.com>
>>> ---
>>>  cgroup.c       |  6 +++++-
>>>  include/util.h |  5 +++++
>>>  util.c         | 26 ++++++++++++++++++++++++++
>>>  3 files changed, 36 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/cgroup.c b/cgroup.c
>>> index 2d9ebad..8b2deb2 100644
>>> --- a/cgroup.c
>>> +++ b/cgroup.c
>>> @@ -258,9 +258,13 @@ static int move_in_cgroup(CgSetEntry *se)
>>>  		int fd, err;
>>>  		ControllerEntry *ce = se->ctls[i];
>>>  
>>> +		sprintf(aux, "%s/%s", ce->name, ce->path);
>>> +		if (mkdirpat(cg, aux) < 0)
>>> +			return -1;
>>> +
>>>  		sprintf(aux, "%s/%s/tasks", ce->name, ce->path);
>>>  		pr_debug("  `-> %s\n", aux);
>>> -		err = fd = openat(cg, aux, O_WRONLY);
>>> +		err = fd = openat(cg, aux, O_WRONLY | O_CREAT, 0700);
>>>  		if (fd >= 0) {
>>>  			/*
>>>  			 * Writing zero into this file moves current
>>> diff --git a/include/util.h b/include/util.h
>>> index 22a0f3d..e2ec22e 100644
>>> --- a/include/util.h
>>> +++ b/include/util.h
>>> @@ -303,4 +303,9 @@ static inline bool strstartswith(char *str, char *sub)
>>>  	}
>>>  }
>>>  
>>> +/*
>>> + * mkdir -p for a file descriptor
>>> + */
>>> +int mkdirpat(int fd, const char* path);
>>> +
>>>  #endif /* __CR_UTIL_H__ */
>>> diff --git a/util.c b/util.c
>>> index 975af30..7d235c6 100644
>>> --- a/util.c
>>> +++ b/util.c
>>> @@ -677,3 +677,29 @@ struct vma_area *alloc_vma_area(void)
>>>  
>>>  	return p;
>>>  }
>>> +
>>> +int mkdirpat(int fd, const char* path)
>>> +{
>>> +	char* tok;
>>> +	char made_path[PATH_MAX] = "", tok_path[PATH_MAX];
>>> +
>>> +	if (strlen(path) < PATH_MAX)
>>> +	{
>>> +		pr_err("path %s is longer than PATH_MAX", path);
>>> +		return -1;
>>> +	}
>>> +
>>> +	strncpy(tok_path, path, PATH_MAX);
>>> +
>>> +	for(tok = strtok(tok_path, "/"); tok; tok = strtok(NULL, "/")) {
>>
>> tok = strtok(NULL, "/") always returns NULL
> 
> Sorry, pls ignore this comment.
> 
>>
>>> +		strcat(made_path, tok);
>>> +		strcat(made_path, "/");
>>> +		if (mkdirat(fd, made_path, 0755) < 0 && errno != EEXIST) {
>>> +			pr_perror("couldn't mkdirpat directory\n");
>>> +			return -1;
>>> +		}
>>> +	}
> 
> Look at my version. It doesn't copy a path in another place.
> 
> 	tok = path;
> 	while (tok = strchr(tok + 1, "/")) {
> 		char c;
> 		if (tok != NULL) {

Is this if necessary?

> 			c = *tok;
> 			*tok = 0;
> 		}
> 
> 		if (mkdirat(fd, path, 0755) < 0 && errno != EEXIST) {
> 			pr_perror("couldn't mkdirpat directory\n");
> 			return -1;
> 		}
> 
> 		if (tok == NULL)

This one?

> 			break;
> 		else
> 			*tok = c;
> 	}
> 
> Thanks.
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>